Patent Application
20140041566
Conventional cargo transport vessels include inland barges transport on inland waterways and ocean going on oceans and limited inland. Inland cargo transport vessels typically transport cargo relatively short distances over inland waterways. Ocean-going cargo transport vessels typically transport cargo relatively long distances over oceans.
A conventional single-hull cargo transport vessel includes a single hull that provides a boundary between the operating environment of the vessel and the cargo. The hull includes a bottom side structural member, a port side structural member, a starboard side structural member, and a topside deck that are connected to form the exterior of the vessel. The hull also includes transverse and longitudinal bulkheads to provide strength, support, and stability to the hull. A cargo carrying volume is formed by the bottom side structural member, port side structural member, starboard side structural member, and topside deck of the vessel. If the hull is breached, cargo may leak from the vessel. To address environmental concerns related to the breach of conventional single-hull cargo transport vessels, governmental regulations now require the use of double-hulls for designated vessels in United States waters.
In accordance with these regulations, a conventional double-hull cargo transport vessel, as approved by current United States Coast Guard and International regulations and standards includes a primary hull and a partial secondary hull that forms a double-hull with respect to the bottom, port, and starboard side of the vessel. A cargo carrying volume is formed by the bottom side structural member, port side structural member, and starboard side structural member of the partial secondary hull and the topside deck of the primary hull. As such, only the portion of the conventional double-hull cargo transport vessel that is in contact with the operating waterline depth environment of the vessel is double-hulled to prevent the leakage of cargo in the event the primary hull is breached.
According to one aspect of one or more embodiments of the present invention, a complete double-hull cargo containment vessel includes a primary hull and a secondary hull disposed within the primary hull. The secondary hull includes one or more interior cargo containment tanks and provides structural integrity to the vessel. The secondary hull includes a topside structural member configured to seal the cargo containment tank or tanks. The cargo tanks can include a split load of materials, such as asphalt and sulfur (sulphur) or a homogenous load of all asphalt or all sulfur.
According to one aspect of one or more embodiments of the present invention, a method of manufacturing a complete integral tank double-hull cargo containment vessel includes the steps of fabricating a primary hull and fabricating a secondary hull disposed within the primary hull. The secondary hull includes one or more interior cargo containment tanks. The secondary hull includes a partial side and complete topside structural member configured to seal the cargo containment tank or tanks.
Other aspects of the present invention will be apparent from the following description and the appended claims.
Specific embodiments of the present invention will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. Further, in the following detailed description of embodiments of the present invention, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. In other instances, well-known features have not been described in detail to avoid obscuring the description of embodiments of the present invention.
A primary hull of the conventional double-hull cargo transport vessel comprises a bottom side structural member 105, a port side structural member 110, a starboard side structural member 115, and a topside deck 120 that are generally formed of steel and joined together to form the primary hull. A transverse frame (or beam) support 108 of the topside deck 120 is shown. Longitudinal frame supports 109 are also shown. A partial secondary hull of the conventional double-hull cargo transport vessel comprises a bottom side structural member 125, a port side structural member 130, and a starboard side structural member 135 that are generally formed of steel and joined together to form the partial secondary hull. This hull configuration of two bottom structural members, two port side structural members, two starboard side structural members, and one topside deck is commonly referred to as “a double-hull configuration” in industry.
The interior cargo carrying volume 106 of the conventional double-hull cargo transport vessel is bounded by a bottom structural member 125, a port side structural member 130, and a starboard side structural member 135 of the partial secondary hull and depending upon the location of the interior cargo carry volume 106, the machinery deck 102 and the topside deck 120 of the primary hull. The cargo carrying volume 106 of the vessel may be partitioned into one or more cargo containment tanks transversely by one or more transverse bulkheads 140 or longitudinally by one or more longitudinal bulkheads 145. In certain areas of the vessel 10, the cargo containment tanks may not include the volume provided in the raised deck portion 104.
The conventional double hull design promotes the use of internal cargo tank framing. External topside framing is exposed to the elements and subject to corrosion/pitting even if protective coatings are applied.
The transport of some cargo requires maintaining the cargo at high temperatures during transport. Exemplars of hot cargo include liquid asphalt, molten sulfur, and molten phenol. Liquid asphalt is typically transported at approximately 325 degrees Fahrenheit. Molten sulfur is typically transported at approximately 300 degrees Fahrenheit. Molten phenol is typically transported at approximately 140 degrees Fahrenheit.
A conventional double-hull cargo transport vessel utilizes one or more diesel-fired heat exchanger to heat one or more layers of heating coils disposed in the cargo tank to maintain hot cargo at its required temperature during transport. The size and number of heat exchangers and heating coils is dependent on the size and configuration of the vessel and the temperature requirements of the cargo to be transported. In addition to the initial cost for installing the heat exchangers and the heating coils, there is a recurring cost for their maintenance.
There is also a substantial fuel cost associated with fueling the heat exchangers during transport. The per transport cost for the diesel fuel required to maintain hot cargo is a substantial portion of the transport cost and is proportional to the duration of the transport. This cost is exacerbated by the fact that, in a conventional double-hull design, there is extensive heat loss through the topside deck structural member, requiring the heat exchangers to use more fuel to maintain the hot cargo at its required temperature.
The use of heat exchangers and heating coils to maintain hot cargo at its required temperature during transport has the unintended consequence of heating the topside deck structural member on which the vessel crew may wish to walk. If the vessel operator wishes to make the topside deck member safe for walking, insulation may be applied to effectively reduce the temperature of the topside deck member. In addition to the substantial cost for the installation of the insulation, there is a substantial recurring cost for maintenance of the insulation and top structural members.
In one or more embodiments of the present invention, a primary hull of a complete double-hull cargo containment vessel comprises a bottom side structural member 205, a port side structural member 210, a starboard side structural member 215, and a topside deck structural member 220 that are generally formed of steel and joined together to form the primary hull. Each of the bottom side structural member 205, the port side structural member 210, the starboard side structural member 215, and the topside deck structural member 220 may individually comprise a plurality of sheet metal panels that are joined to form the respective structural members used to form the primary hull. Because unsupported sheet metal can deform when a force is exerted on it, reinforcements are used to provide strength and stability to the primary hull. The topside deck structural member 220 comprises a plurality of longitudinal panel stiffening beams 245 that are joined to the topside deck structural member 220. Each longitudinal panel stiffening beam 245 is generally comprised of sheet metal. One of ordinary skill in the art will recognize that the number, orientation, and configuration of panel stiffening beams may vary in accordance with one or more embodiments of the present invention. The primary hull is water tight and serves as a first boundary between the operating environment of the vessel and the cargo.
In accordance with one or more embodiments of the present invention, a secondary hull of a complete double-hull cargo containment vessel comprises a bottom side structural member 225, a port side structural member 230, a starboard side structural member 235, a topside structural member 240 and a structural member 33 for the raised trunk portion 21 (at main deck level) that are generally formed of steel and joined together to form a complete secondary hull that is integrally disposed within the primary hull. Each of the bottom side structural member 225, the port side structural member 230, the starboard side structural member 235, the topside structural member 240 and the structural member 33 may generally comprise a plurality of sheet metal panels that are joined to form the respective structural members used to form the secondary hull. The various members are integral to the structural integrity of the vessel. Advantageously, cargo may be contained within the secondary hull separate and apart from the primary hull, and the secondary hull is itself disposed within the primary hull. As a consequence, the secondary hull is oil or chemical tight and serves as a second boundary between the operating environment of the vessel and the cargo.
The complete double-hull provides strength and structural support to the vessel greater than a conventional double-hull cargo transport vessel. In one or more embodiments of the present invention, the topside structural member 240 is generally comprised of sheet metal. Because unsupported sheet metal can deform when a force is exerted on it, reinforcements can be used to provide strength and stability to the secondary hull. In one or more embodiments of the present invention, panel stiffening supports or beams are used for reinforcement.
Advantageously, because the secondary hull is disposed within the primary hull and the canopy formed by the topside structural member 240 of the secondary hull is covered by the topside deck structural member 220 of the primary hull, in one or more embodiments of the present invention, longitudinal corrugated sheet metal may be used for reinforcement of the topside structural member 240 without concern for standing water and corrosion.
Advantageously, the use of corrugated sheet metal panels 305 to form the topside structural member 240 of the secondary reduces costs associated with the application, removal, and re-application of special coatings to one or more cargo containment tanks. If the topside structural member 240 is comprised of panel stiffening beams 245, the interior of one or more cargo containment tanks are not smooth and applied coating substances can build up at the interface of the panel stiffening beams 246 and the topside structural member 240. If the topside structural member 240 is comprised of corrugated sheet metal panels 305, the interior of one or more cargo containment tanks are smooth and applied coating substances can more easily be applied, removed, and re-applied. This reduces maintenance costs associated with the use of coatings.
Returning to
The cargo carrying volume 221 may be partitioned into one or more cargo containment tanks 260. The cargo carrying volume may be partitioned transversely by one or more transverse bulkheads 250 and/or longitudinally by one or more longitudinal bulkheads 255. One or more of the transverse bulkheads 250 may be formed of corrugated sheet metal panels 305. One or more of the longitudinal bulkheads 255 may be formed of corrugated sheet metal panels 305. The one or more cargo containment tanks of the secondary hull are sealed by the topside structural member 240 of the secondary hull. Various or homogenous materials may be contained in the various compartment tanks depending on a customer's requirement.
In one or more embodiments of the present invention, one or more heating coils 265 are disposed within cargo containment tank 260. Advantageously, in one or more embodiments of the present invention, the entire interior cargo carrying volume of the complete double-hull cargo containment vessel is disposed within the secondary hull that is itself disposed within the primary hull. As such, the secondary hull is insulated by the primary hull. Thus, in a complete double-hull cargo containment vessel, heat loss through the topside deck structural member 220 is substantially less than that of a conventional double-hull cargo transport vessel. As a consequence, the complete double-hull reduces vessel fabrication costs and energy costs associated with maintaining hot cargo at its required temperature during transport.
Advantageously, in one or more embodiments of the present invention and shown in
Because of the insulation provided by the complete double-hull, the amount of fuel required to power one or more heat exchangers 270 that drives one or more heating coils 265, is substantially reduced. This results in substantial per transport fuel cost savings over a conventional double-hull cargo transport vessel. In addition, the size and number of heating coils 265 disposed within each cargo containment tank 260 may be reduced because fewer heating coils 265 are required in a complete double-hull cargo containment vessel than in a conventional double-hull cargo transport vessel with similarly size cargo tank or tanks to maintain hot cargo at its required temperature during transport. As a result, vessel fabrication costs associated with the heating coils 265 are reduced and the energy costs associated with maintaining hot cargo at its required temperature during transport is substantially reduced.
Further, because of the insulation provided by the complete double-hull, the temperature of topside deck, on which vessel crew may walk, is greatly reduced. As a result, insulation is not required to make the topside deck member walkable. This reduces the costs typically associated with insulating the topside deck in a conventional double-hull cargo transport vessel or the cost of human protection devices. However, if desired, insulating materials may be added to the void space created by the complete integral double hull design.
In one or more embodiments of the present invention, a draft line of a complete double-hull cargo containment vessel is established, in part, by the exterior of the vessel defined by the primary hull, the cargo carrying volume of the secondary hull, and the apparent specific gravity of the cargo in one or more cargo containment tanks. The apparent specific gravity of cargo is a ratio of the weight of the volume of cargo to the weight of an equal volume of a reference substance, for example, water. The apparent specific gravity of liquid asphalt is approximately 1.1 at transport temperature and the apparent specific gravity of molten sulfur is approximately 1.8 at transport temperature. Because these cargos have a different specific gravity, the amount that can be transported in a given vessel, and meet the draft requirements, differs from one another. For example, a given volume of a substance with a higher specific gravity weighs more than an equal volume of a substance with a lower specific gravity. As such, the amount of cargo that can be transported in a given cargo carrying volume, within the draft requirements of the vessel, differs based on the cargo transported. Moreover, a specific cargo may require a special coating to be applied to a cargo containment tank whereas a different cargo may require a different special coating to be applied to a cargo containment tank.
In one or more embodiments of the present invention, two longitudinal bulkheads 255 partition the cargo carrying volume of the secondary hull into three cargo containment tanks 260. The port side and starboard side cargo containment tanks 260 are dedicated to the transport of liquid asphalt. The port side and starboard side cargo containment tanks 260 may be coated with a special coating required by the liquid asphalt. One of ordinary skill in the art will recognize that a different cargo may be used in the place of liquid asphalt in accordance with one or more embodiments of the present invention. The middle cargo containment tank 260 may be dedicated to the transport of molten sulfur. The middle cargo containment tank 260 may be coated with a special coating required by molten sulfur. One of ordinary skill in the art will recognize that a different cargo may be used in the place of molten sulfur in accordance with one more embodiments of the present invention. Thus, a complete double-hull cargo containment vessel may have port and starboard side cargo containment tanks 260 coated for one cargo and a middle cargo containment tank 260 that is coated for a different cargo.
Advantageously, this configuration allows a complete double-hull cargo containment vessel to transport liquid asphalt and molten sulfur without modification to or turnaround service on the vessel. For example, the port and starboard side cargo containment tanks 260 are prepared for liquid asphalt cargo and the middle cargo containment tank 260 is prepared for molten sulfur. As such, a complete double-hull cargo containment vessel may transport liquid asphalt up river to one destination and then transport molten sulfur down river to another destination without requiring a turnaround service on the vessel. However, in another embodiment, rather than a split load, the vessel can transport homogenous materials, such as all asphalt or all sulfur in the cargo tanks. Thus, a complete integral double-hull cargo containment vessel is more efficient, provides cost savings, and can generate higher transport revenues than a conventional double-hull cargo transport vessel.
In step S3, one or more cargo containment tanks are fabricated within the secondary hull of the vessel. One or more transverse bulkheads may be used to partition the secondary hull to form one or more cargo containment tanks. One or more longitudinal bulkheads may be used to partition the secondary hull to form one or more cargo containment tanks. In one or more embodiments of the present invention, two longitudinal bulkheads are fabricated to partition the secondary hull cargo carrying volume into three cargo containment tanks. In one or more embodiments of the present invention, the three cargo containment tanks are configured to facilitate the transport of different cargos without turnaround service. The cargo containment tanks are sealed by the secondary hull, which is itself disposed within the primary hull of the vessel. One of ordinary skill in the art will recognize that the fabrication of the cargo containment tanks may be in part and taken out of order with other steps to facilitate the fabrication of the vessel. In step S4, one or more heat exchangers are disposed on or within the vessel and secured in place. One of ordinary skill in the art will recognize that the disposing of and securing of the one or more heat exchangers may be in part and taken out of order with other steps to facilitate the fabrication of the vessel. In step S5, one or more heating coils are disposed within each of the one or more cargo containment tanks. One of ordinary skill in the art will recognize that the disposing of the one or more heating coils within each of the one or more cargo containment tanks may be in part and taken out of order with other steps to facilitate the fabrication of the vessel.
Advantages of one or more embodiments of the present invention may include one or more of the following.
In one or more embodiments of the present invention, a complete integral double-hull cargo containment vessel reduces energy costs associated with transporting hot cargo.
In one or more embodiments of the present invention, a complete integral double-hull cargo containment vessel requires a smaller heat exchanger than a conventional cargo vessel with a similarly sized cargo tank to maintain hot cargo at its required temperature during transport. As a consequence, the heat exchanger has a reduced physical footprint on the vessel.
In one or more embodiments of the present invention, a complete integral double-hull cargo containment vessel requires fewer heating coils than a conventional cargo vessel with a similarly sized cargo tank to maintain hot cargo at its required temperature during transport. As a consequence, there is more tank volume for the storage of cargo.
In one or more embodiments of the present invention, a complete integral double-hull cargo containment vessel requires less diesel to fuel the heat exchanger and heating coils than a conventional cargo vessel with a similarly sized cargo tank to maintain hot cargo at its required temperature during transport. As a consequence, the fuel costs are substantially reduced.
In one or more embodiments of the present invention, a complete integral double-hull cargo containment vessel provides increased strength and structural support to the vessel than a conventional cargo vessel.
In one or more embodiments of the present invention, a complete integral double-hull cargo containment vessel reduces the temperature of the topside deck of the primary hull.
In one or more embodiments of the present invention, a complete integral double-hull cargo containment vessel eliminates or reduces the need for insulating the topside deck structural member of the primary hull.
In one or more embodiments of the present invention, a complete integral double- hull cargo containment vessel eliminates or reduces maintenance associated with insulating the topside deck structural member of the primary hull.
In one or more embodiments of the present invention, a complete integral double-hull cargo containment vessel may use corrugated sheet metal panels for portions of the secondary hull because it is insulated from water by the primary hull.
In one or more embodiments of the present invention, a complete integral double-hull cargo containment vessel that uses corrugated sheet metal panels to form the topside structural member of the secondary hull allows for cargo containment tanks that are smooth.
In one or more embodiments of the present invention, a complete integral double-hull cargo containment vessel has one or more smooth cargo containment tanks that reduce costs associated with applying, removing, and re-applying special coatings required by specific cargos.
In one or more embodiments of the present invention, a complete integral double hull-cargo containment vessel has port and starboard side cargo containment tanks configured to carry one type of cargo and a middle cargo containment tank configured to carry another type of cargo.
In one or more embodiments of the present invention, a complete integral double-hull cargo containment vessel with port and starboard side cargo containment tanks configured to carry one type of cargo and a middle cargo containment tank configured to carry another type of cargo can transport both types of cargo without turnaround service.
In one or more embodiments of the present invention, a complete integral double-hull cargo containment vessel with port and starboard side cargo containment tanks configured to carry one type of cargo in all tanks without turnaround service.
In one or more embodiments of the present invention, a method for transporting a mix of cargoes, such as heated asphalt and heated sulfur, in separate heated cargo containment tanks of a complete integral double-hull cargo containment vessel.
In one or more embodiments of the present invention, a method for transporting a mix of cargoes, such as materials that require heating in one containment tank and materials that do not require heating in another containment tank of a complete integral double-hull cargo containment vessel
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.
